Field of the Invention
This invention is a device for towing one vehicle by another vehicle when neither vehicle in itself is equipped with a "tongue". Examples are; a Motor Home towing an automobile ("jitney"), a truck towing a smaller pickup truck or jeep, a grader towing a pickup truck, etc.
Simple "A Frame Type" tow bars have been in existence for years. These are often quite heavy with the design and construction intended for commercial applications. The size and weight of the tow bar device and method of attachment to the towed vehicle precludes easy removal and storage of the tow bar.
Over the last few years, more portable, light duty "tow bars" have come onto the market. These devices address the Motor Home and tow car ("jitney") market. Some of these are quite sophisticated . . . employing self aligning pistons or shafts, fold up features and so on. Some are quite complicated with multiple moving parts and adjustment mechanisms.
Most of the existing tow bar devices are attached to the front of the towed vehicle through the use of multiple attachments (e.g. pins or couplers to the frame of the jitney), and are fastened to a trailer hitch/ball mount on the rear of the towing vehicle. Most of them employ two "draw bars" that triangulate from the rear of the Motor Home to the front of the "jitney".
These prior art and market place available devices all differ from this application (Morrill tow bar) in that attachment to the rear of the towing vehicle is by means of a trailer hitch ball coupler and all of them employ multiple attachments to the front of the towed vehicle.
This application (Morrill tow bar) displays rigid attachment to the rear of the towing vehicle, a single segmented tow bar shaft and one ball/coupler in the center of the front of the towed vehicle.
Seven patents were found that employ single shafts (one of these actually employs two "single" shafts) as a tow bar. These are listed and discussed below:
Invention Title Inventor U.S. Pat. No. 5,226,657 Vehicle Towing Means Dolphin, William A. 4,194,755 Tow Bar For Vehicles Youngblood, John W. 3,342,508 Auxiliary Universal Thomas, G. I. Tow Bar for Boat Trailers 4,372,568 Luggage and Accessory Campbell, James H. Trailer 4,588,199 Swivel Connection for Fisher, William E. Trailers WIPO NO. WO 92/05040 Improved Tow Bar Williams, Gregory J. GER NO. 2,225,540 Fahrgestell fur Wohnwagen Amtenbrink, Freidrich
Each of these patents display specialized devices which are designed for unique circumstances. None of them display features suitable for the general tow bar market. None of them are suitable for the motor home and accessory vehicle ("jitney") market.
The Dolphin patent discloses a segmented single shaft. However this "single shaft" actually includes a compound frame structure and multiple moving parts including a crank/screw arrangement. Further, the patent discloses that this device was designed for the specific purpose of towing golf carts with the rear wheels in an elevated position. The features of this patent (crank/screw arrangement for elevating the golf cart rear wheels) which are unique are superfluous to a general usage tow bar (e.g. for Motor homes and towed cars).
The attachment to the rear of the towing vehicle is by means of a trailer hitch coupler/ball arrangement. The wording in the claims relative to the connection to the towing vehicle ("said hitch connector") is vague and ambiguous. However, the patent clearly discloses elsewhere that the "hitch connector" is a "hitch ball member" or "ball hitch assembly" which is attached to the "rear bumper member".
Careful review of this patent and the patent drawings raises serious doubt that the device is even functional in that there is no apparent mechanism to prevent the coupler from rotating downward on the "ball hitch assembly" when the crank/screw is employed to straighten the tow bar shaft segments.
The Dolphin patent is not really at all similar in design or purpose to this application (Morrill towbar). This is readily apparent when the characteristics of this application (Morrill tow bar) below and in the "Summary" herein are reviewed.
The Youngblood patent discloses a device to elevate the front wheels of a towed vehicle, specifically a "front wheel drive vehicle". It is very similar in purpose to the Campbel patent although intended for a much more heavy towed vehicle. It differs from the Campbell patent device in that it does display a chain/winch arrangement to hold the trailer hitch/coupler in a horizontal position when the tow bar is straightened to raise the towed vehicle. The attachment to the rear of the towing vehicle is by means of a trailer hitch coupler/ball and the cable winch apparatus. The device employs multiple attachment components to accomplish attachment to the chassis of the towed vehicle. The Youngblood patent device has multiple moving parts and complicated mechanisms compared to this application (Morrill tow bar).
The Thomas patent discloses a device which pivots at the draw bar attachment with intended facilitation of the loading and unloading of a boat from a boat trailer.
The Campbell patent is actually a "Luggage and Accessory Trailer" and is not really relevant to this application except for the fact that the trailer employs a single shaft tongue which could be construed as a "tow bar" in that it is detachable from the trailer by means of a receiver/sting arrangement and pin.
There is nothing in the patent descriptions or the "claims" to suggest that this "single shaft trailer tongue" is "anticipated" as a "tow bar" for towing one vehicle by another. Indeed, the language throughout the patent clearly discloses "small utility trailers that can be towed behind small vehicles".
The Fisher patent discloses a swivel connection to facilitate connection of a small trailer to a motorcycle. It is true the claims do not restrict the anticipated use to motor cycles and trailers. However, there is no effort in the claims to cover the towbar itself. The claims cover a spindle/swivel arrangement between the tongue of the trailer and the vehicle hitch assembly, for the purpose of enabling vertical; and horizontal rotation of the motor cycle relative to the trailer. This is a very narrow objective, solving the very specific problem that is encountered when a trailer is towed behind a motorcycle (i.e. The motor cycle leans to one side or the other when in operation and when parked while the two wheeled trailer does not). This patent obviously does not anticipate a tow bar for general usage.
The Williams patent discloses a device consisting of two tow bars to connect the bumper of a disabled vehicle to a towing vehicle, especially for retrieval of the disabled vehicle over rough terrain.
The Amtenbrink patent is in German. However, the drawing clearly discloses a tongue ( not a detachable tow bar) which is attached to the front of a "wagon" (camper trailer) with a yoke and one or two front wheels and which attaches to the rear of the towing vehicle by means of a trailer hitch ball and coupler arrangement. This arrangement is referred to as a "pull trailer" and facilitates towing of a heavy trailer by a vehicle which is too small to bear the weight of the front of a trailer.
Each of these seven prior art differ from this application (Morrill tow bar) as discussed above and as follows;
1. Attachment to the towing vehicle is by means of a ball hitch/coupler assembly (not rigid). PA1 2. Attachment to the front of the towed vehicle is rigid--in most cases employing multiple and complicated coupling components or permanent. PA1 3. The objectives are very specific and unique--not intended for general tow bar circumstances.
Applicant's review of prior art included many other patents that bear some similarity to this application (Morrill towbar).However, all of the prior art that was discovered, including the seven specifically enumerated above, share one or more of the following features and disadvantages.
1. Attachment to the rear of the towing vehicle is by means of a trailer hitch ball and coupler at the rear of the towing vehicle.
2. Attachment to the towed vehicle is achieved by multiple and comparatively complicated connecting devices.
One disadvantage of the prior art features Number one and two above, is the fact that the tow bar must either be folded and secured on the front of the towed vehicle when the towing operation is suspended, or removed from the front of the towed vehicle and stored separately. On the one hand, removal from the towed vehicle is time consuming and relatively complicated and the tow bar then is awkward to store.
On the other hand the tow bar folded and secured on the front of the "towed vehicle" is bulky and unsightly. Those models that fold vertically in front of the "towed vehicle" grill partially obscure visibility and present an additional hazard (the towbar falls down in front of the "towed vehicle" if the device that secures it fails).
Another disadvantage to these features is the fact that the vehicles cannot be backed up when coupled together without "jack knifing".
3. The prior art are all relatively complicated, usually with multiple moving parts.
One disadvantage is the resultant high cost of manufacturing. Another disadvantage is the increase in maintenance. Another disadvantage is the difficulty in coupling and uncoupling the two vehicles and activating the features of the various devices.
A number of tow bar devices have recently appeared on the market which are attached to the rear of the Motor Home or towing vehicle, and are similar in this respect to this application (Morrill towbar). This applicant was unable to discover patents covering these tow bars. There are patents covering various components ( e.g. Joints, etc.).
None of these tow bars employ the concept of rigid attachment to the rear of the towing vehicle combined with attachment at a single point In the center of the front of the towed vehicle. None of them have the feature of a vertically pivotable joint directly behind the attachment to the towed vehicle. Each of these other tow bars consist of multiple shafts and multiple attachments to the front of the towed vehicle by means of various pin and fastener devices which are vertically rotatable, but horizontally rigid to the towed vehicle. In each case, horizontal rotation is provided by relatively complex flexible joint (either directly behind the attachment to the towing vehicle or midway between the two vehicles).
Accordingly, the disadvantages enumerated above apply to these tow bars as well except that the tow bar can be removed from the towed vehicle and left hanging on the rear of the towing vehicle when not in use.
The applicant has observed and determined that removal from; and reattachment to, the front of the towed vehicle, is relatively difficult and time consuming due to the multiple tow bar shafts (which must be centered and aligned) and relatively complicated means of attachment to the front of the towed vehicle. This is especially true if the axis of the towing and towed vehicle differ either vertically or horizontally.
This application (Morrill tow bar) overcomes these disadvantages as outlined in the "Summary" below.